Patent EA-001576-B1 (EA)
Title: Substrate producing three-dimentional images
Inventor: DUNN PAUL
IPC: G02B30/20
Filed: 1997-08-18
Abstract: 1) A substrate which is arranged to present a three-dimensional optical image to a viewer, the substrate being formed with a plurality of stereo pairs of optical elements (14,16) each pair of optical elements being arranged to direct light to the respective eyes of a viewer, when positioned at a predetermined angle of view or within a limited range of angles of view, and so give the viewer an image of a point (P) at a predetermined distance from the plane of the substrate on crossing of the lines along which light beams move from corresponding elements of a pair wherein a plurality of pairs of optical elements (14,16) being arranged on the substrate with a different orientation in respect of X and Y axes so that the corresponding plurality of point images (P) which they provide form said three-dimensional image. 2) A substrate as claimed in claim 1, in which said optical elements (14, 16) are arranged to reflect incident light to the viewer. 3) A substrate as claimed in claim 1, in which said optical elements (14, 16) are arranged to refract light transmitted through the substrate to the viewer. 4) A substrate as claimed in any one of claims 1 to 3, in which said optical elements (14, 16) comprise grooves formed in the surface of the substrate. 5) A substrate as claimed in any one of claims 1 to 3, in which said optical elements (14, 16) comprise ridges formed on the surface of the substrate. 6) A substrate as claimed in claim 2, in which said optical elements (14, 16) comprise reflective printing formed on the surface of the substrate.  7) A substrate as claimed in any preceding claim, in which each said pair of optical elements comprises two short linear elements the relative orientations of which determine the distance of the corresponding point image (P) from the surface of the substrate. 8) A substrate as claimed in any preceding claim, in which, for each point image, a set of said pairs of optical elements (14, 16) are provided, such that equivalent point images are visible from different angles of view. 9) A substrate as claimed in claim 8, in which, for at least one said point image, the optical elements (14, 16) relating to that point image are displaced from a common line. 10) A substrate as claimed in claim 9, in which, for at least one said point image, the optical elements (14, 16) relating to that point image are positioned on a common horizontal line. 11) A substrate as claimed in claim 8, in which, for at least some of said point images, selected pairs of optical elements are omitted such that those points are obscured for selected angles of view, thus providing hidden line and/or hidden surface removal in respect of the three-dimensional image. 12) A substrate as claimed in any preceding claim, in which at least some of said point images (P) together define a linear image. 13) A substrate as claimed in any preceding claim, in which at least some of said point images (P) together define shading to provide the image of a surface of a three-dimensional object. 14) A substrate as claimed in claim 15, in which said point images define shading to provide the image of a plurality of surfaces of a three-dimensional object, in which the density of said optical elements for relatively oblique surfaces of the three-dimensional object are reduced in comparison to the optical elements for less-oblique surfaces of said object. 15) A substrate as claimed in any preceding claim, arranged to present a plurality of optical images to a viewer, said optical images being visible from different angles of view. 16) A substrate as claimed in any preceding claim, in which the optical elements of different pairs have different cross-sectional profiles to control image brightness and/or image shading and/or angle of view.